Determining primary product ion from the mesoscale oxygen field

Net biological oxygen production can be determined from models of time-series measurements of the oxygen field, so long as there are simultaneous measurements of inert gas tracers to estimate the role of air-water transfer and mixing with the ocean interior. In the two locations where this has been done, the oxygen balance yields net nutrient production values that are within a factor of three of sediment trap and in vitro incubation experiments. Initial findings from a similar study at the US JGOFS time­series station near Hawaii (Station ALOHA) reveal that nitrogen uptake determined by net biological O₂ production in the upper 175 m, which includes both the euphotic and shallow respiration zones, agrees to within a factor of two of the mean annual sediment trap N flux at 150 m. Poorly known processes that should be explored to reconcile differences in the various methods are: (a) transport of dissolved and suspended particulate organic matter out of the euphotic zone, (b) alteration of O₂:DIC:NO₃ stoichiometry in the euphotic zone by production of carbon-rich dis­solved organic matter, and (c) bacterial heterotrophic NO₃ uptake.

Article from Marine Science Symposia Vol. 197 - "Measurement of Primary Production from the Molecular to the Global Scale". Symposium held in La Rochelle, 21-24 April 1992. To access the remaining articles please click on the keyword "MSS Vol. 197".